The Otii Arc Pro has the voltage(+) and voltage(-) binding post (red and black connectors located on the right side of the instrument), which are used to source the DUT but also to measure the current, voltage, and power of the device. The DUT can be connected through its battery connectors or DC input; refer to the connection diagram below for better understanding.

Arc connected to DUT

To power up the Otii Arc Pro and enable communication with the host computer, connect the unit to your computer using the provided USB micro B to USB A cable.

Arc connected to a computer

Check out the Wiring up page to explore all possible connection configurations between the Otii Arc Pro and your DUT.

Expansion Port

The expansion port on the front of the Otii Arc Pro is designed to enhance the hardware's functionality, allowing users to measure additional voltages and currents or trigger external events. These additional pins feature multi-input and multi-output for analog and digital signals, serial communication, and additional power and ground points. Below is a general overview of the additional pins available:

Connector	Description	Maximum rating
+5V	5 V output	500 mA
DGND	Digital ground (return current)
RX	UART RX / Digital Input (Exclusively under Scripting)	0 V to 5.5 V
TX	UART TX / Digital Output (Exclusively under Scripting)	0 V to 5.5 V
GPI1	Digital input 1	0 V to 5.5 V
GPI2	Digital input 2	0 V to 5.5 V
GPO1	Digital Output 1	0 V to 5.5 V
GPO2	Digital Output 2	0 V to 5.5 V
DGND	Digital ground (return current)
AGND	Analog ground (return current) / Analog measurements
ADC+	Differential input for current measurement. It also measures single ended voltage with respect to AGND	0 V to 5.5 V
ADC-	Input for current measurement	0 V to 5.5 V
SENSE+	Analog input with the AGND as reference/return	0 V to 5.5 V
SENSE-	Analog input with the AGND as reference/return	0 V to 5.5 V

Status LED

The table below explains the Otii Arc Pro's status LED behaviors and their meanings to help you quickly identify the device's state.

LED behavior	Otii Arc Pro Status
Flashing green	Otii Arc Pro is active
Solid green	Relay closed, sinking/sourcing power

Arc Tech spec

General

Operating environment	Min	Typical	Max
Temperature	10°C / 50°F		30°C / 86°F
Humidity	30 %		60 %

USB power supply ¹	Min	Typical	Max
Output voltage (auto range)	0.5 V		3.75 V
Output voltage (locked to high current range)	0.5 V		4.2 V
Output voltage setting resolution		1 mV
Output current, max continuous ³		up to 1 A ¹	2.4 A
Output current, max peak ³		up to 1 A ¹	5 A

External 7.5 v - 9 v power supply ²	Min	Typical	Max
Output voltage (auto range)	0.5 V		4.55 V
Output voltage (locked to high current range)	0.5 V		5.0 V
Output voltage setting resolution		1 mV
Output current, max continuous ³			2.4 A
Output current, max peak ³			5 A

Programmable current sink (requires an Otii Toolbox)	Min	Typical	Max
Sink current	0 A		2.5 A
Sink current, setting resolution		39 µA
Sink voltage, USB power supply	0.85 V ⁴		4.2 V
Sink voltage, external power supply	0.85 V ⁴		5.0 V

Current measurement	Min	Typical	Max
Accuracy		±(0.1 % + 50 nA)⁵
Sample Rate in ±19 mA range		4 ksps
Sample Rate in ±2.7A range		1 ksps
Sample Rate in ±5.0 A range		1 ksps
Analog bandwidth (3 dB)		400 Hz

Voltage measurement	Min	Typical	Max
Total accuracy		±(0.1 % + 1.5 mV)
Sample rate		1 ksps

Expansion port

UART	Min	Typical	Max
Bitrate	110 bps		5.25 Mbps

Digital I/O ⁶	Min	Typical	Max
Digital IO operating voltage	1.2 V	Vio ⁷	5 V ⁸
VIL Low-level input voltage			Vio * 0.2 V
VIH High-level input voltage	Vio * 0.8 V
Imax, Max sink/source current (total for GPIOs)	-10 mA		10 mA

Differential ADC, pins ADC- and ADC+ ⁹	Min	Typical	Max
Voltage input	0 V		5 V
Shunt voltage range	-81.9175 mV		81.2 mV
Resolution		2.5 µV
Accuracy		±(0.1 % + 10 µV)
Input impedance		220 kΩ

Single ended ADC, pins ADC- and ADC+ ⁹	Min	Typical	Max
Voltage input	0 V		5 V
Resolution		1.25 mV
Accuracy		±(0.1 % + 7.5 mV)
Input impedance		830 kΩ

SENSE, pins SENSE- and SENSE+	Min	Typical	Max
Voltage input	0 V		5 V
Resolution		1.5 mV
Accuracy		1 %
Input impedance		1 MΩ

Expansion port power supply	Min	Typical	Max
Output voltage		5 V ¹⁰
Output current		500 mA

USB and DC jack

DC jack	Min	Typical	Max
Input voltage	7 V		9 V
Input current			5 A

USB	Min	Typical	Max
VBUS voltage	4.75 V		5.25 V
VBUS current			3 A